The study of phenotypic plasticity has progressed significantly over the past few decades. We have moved from variation for plasticity being considered as a nuisance in evolutionary studies to it being the primary target of investigations that use an array of methods, including quantitative and molecular genetics, as well as of several approaches that model the evolution of plastic responses. Here, I consider some of the major aspects of research on phenotypic plasticity, assessing where progress has been (...) made and where additional effort is required. I suggest that some areas of research, such the study of the quantitative genetic underpinning of plasticity, have been either settled in broad outline or superseded by new approaches and questions. Other issues, such as the costs of plasticity are currently at the forefront of research in this field, and are likely to be areas of major future development. (shrink)

How much can we shape the emotions we experience? Or to put it another way, how plastic are our emotions? It is clear that the exercise of identifying the degree of plasticity of emotion is futile without a prior specification of what can be plastic, so we first propose an analysis of the components of emotions. We will then turn to empirical data that might be used to assess the degree of plasticity of emotions.

and apply it to various examples of neural plasticity in which input is rerouted intermodally or intramodally to nonstandard cortical targets. In some cases but not others, cortical activity ‘defers’ to the nonstandard sources of input. We ask why, consider some possible explanations, and propose a dynamic sensorimotor hypothesis. We believe that this distinction is important and worthy of further study, both philosophical and empirical, whether or not our hypothesis turns out to be correct. In particular, the question of (...) how the distinction should be explained is linked to explanatory gap issues for consciousness. Comparative and absolute explanatory gaps should be distinguished: why does neural activity in a particular area of cortex have this qualitative expression rather than that, and why does it have any qualitative expression at all? We use the dominance/deference distinction to address the comparative gaps, both intermodal and intramodal (not the absolute gap). We do so not by inward scrutiny but rather by expanding our gaze to include relations between brain, body and environment. (shrink)

Churchland's paper "Perceptual Plasticity and Theoretical Neutrality" offers empirical, semantical and epistemological arguments intended to show that the cognitive impenetrability of perception "does not establish a theory-neutral foundation for knowledge" and that the psychological account of perceptual encapsulation that I set forth in The Modularity of Mind "[is] almost certainly false". The present paper considers these arguments in detail and dismisses them.

This paper considers the connections between semantic shiftiness (plasticity), epistemic safety and an epistemic theory of vagueness as presented and defended by Williamson (1996a, b, 1997a, b). Williamson explains ignorance of the precise intension of vague words as rooted in insensitivity to semantic shifts: one’s inability to detect small shifts in intension for a vague word results in a lack of knowledge of the word’s intension. Williamson’s explanation, however, falls short of accounting for ignorance of intension.

Merleau-Ponty’s explication of concrete or practical movement by way of the Schneider case could be read as ending up close to automatism, neglecting its flexibility and plasticity in the face of obstacles. It can be contended that he already goes off course in his explication of Schneider’s condition. Rasmus Jensen has argued that he assimilates a normal person’s motor intentionality to the patient’s, thereby generating a vacuity problem. I argue that Schneider’s difficulties with certain movements point to a means (...) of broadening Merleau-Ponty’s account of concrete movement, one that he broaches without exploiting. What could do more work is his recognition of a transposition capacity - and hence of a plasticity - in the healthy body’s skill schema. As well as avoiding vacuity, he could forestall the appearance of a dichotomy between practical coping and creativity. (shrink)

Some of Catherine Malabou’s recent work has developed her conception of plasticity (originally deployed in a reading of Hegelian Aufhebung ) in relation to neuroscience. This development clarifies and advances her attempt to bring contemporary theory into dialogue with the natural sciences, while indirectly indicating her engagement with the French tradition in philosophy of science and philosophy of medicine, especially the work of Georges Canguilhem. I argue that we can see her development of plasticity as an answer to (...) some specific shortcomings in Canguilhem’s conception of organic or biological normativity as advanced in The Normal and the Pathological . Such a view of plasticity shows its potential to provide the basis for a powerful critical engagement with contemporary conceptions of selfhood, self-transformation, subjectivation, and the general theory of norms. (shrink)

Consciousness is typically construed as being explainable purely in terms of either private, raw feels or higher-order, reflective representations. In contrast to this false dichotomy, we propose a new view of consciousness as an interactive, plastic phenomenon open to sociocultural influence. We take up our account of consciousness from the observation of radical cortical neuroplasticity in human development. Accordingly, we draw upon recent research on macroscopic neural networks, including the “default mode”, to illustrate cases in which an individual’s particular “connectome” (...) is shaped by encultured social practices that depend upon and influence phenomenal and reflective consciousness. On our account, the dynamically interacting connectivity of these networks bring about important individual differences in conscious experience and determine what is “present” in consciousness. Further, we argue that the organization of the brain into discrete anti-correlated networks supports the phenomenological distinction of prereflective and reflective consciousness, but we emphasize that this finding must be interpreted in light of the dynamic, category-resistant nature of consciousness. Our account motivates philosophical and empirical hypotheses regarding the appropriate time-scale and function of neuroplastic adaptation, the relation of high and low frequency neural activity to consciousness and cognitive plasticity, and the role of ritual social practices in neural development and cognitive function. (shrink)

The basic problem of perceptual change is how to account for both variation and constancy in perceiving the world. Is order learned? How deep does plasticity go in that respect? I argue that different kinds of perceptual plasticity have been confused in recent debates, notably between J. Fodor and P. M. Churchland. By focusing on changes in the use of concepts, the issues in the Fodor-Churchland debate can be resolved. Beyond that debate, I propose a generalized encoding approach (...) to perception as a way of accounting for a significant form of perceptual change. (shrink)

Phenotypic plasticity integrates the insights of ecological genetics, developmental biology, and evolutionary theory. Plasticity research asks foundational questions about how living organisms are capable of variation in their genetic makeup and in their responses to environmental factors. For instance, how do novel adaptive phenotypes originate? How do organisms detect and respond to stressful environments? What is the balance between genetic or natural constraints (such as gravity) and natural selection? The author begins by defining phenotypic plasticity and detailing (...) its history, including important experiments and methods of statistical and graphical analysis. He then provides extended examples of the molecular basis of plasticity, the plasticity of development, the ecology of plastic responses, and the role of costs and constraints in the evolution of plasticity. A brief epilogue looks at how plasticity studies shed light on the nature/nurture debate in the popular media. (shrink)

This essay defends the view that, as embodied, our identities are necessarily dependent on the aesthetic environment. Toward this end, it examines the renewal of the concept of sensation (aisthesis) in phenomenology, but then concludes that the methodology and metaphysics of phenomenology must be abandoned in favor of an ontology that sees corporeal identity as generated by the materiality of aesthetic relations. It is suggested that such an ontology is available in the work of Spinoza, which helps break down the (...) natural/ artificial and human/nonhuman distinctions, and can thereby engender an environmental ethics grounded in aesthetic relations. An explication of body/ world dependence is provided via the concept of plasticity and a properly Spinozist aesthetics is invoked, but remains to be worked out. (shrink)

In recent years, many scholars have suggested that the Baldwin effect may play an important role in the evolution of language. However, the Baldwin effect is a multifaceted and controversial process and the assessment of its connection with language is difficult without a formal model. This paper provides a first step in this direction. We examine a game-theoretic model of the interaction between plasticity (represented by Herrnstein reinforcement learning) and evolution in the context of a simple language (...) game. Additionally, we describe three distinct aspects of the Baldwin effect: the Simpson–Baldwin effect, the Baldwin expediting effect and the Baldwin optimizing effect. We find that a simple model of the evolution of language lends theoretical plausibility to the existence of the Simpson–Baldwin and the Baldwin optimizing effects in this arena, but not the Baldwin expediting effect. (shrink)

Recent developments in cognitive science provide compelling leads that need to be interpreted and synthesized within the context of semiotic and biosemiotic principles. To this end, we examine the impact of the mind-body unity on the sorts of choices that an organism is predisposed to making from its Umwelt. In multicellular organisms with brains, the relationship that an organism has with its Umwelt impacts on neural plasticity, the functional specialisations that develop within the brain, and its behaviour. Clinical observations, (...) such as those recorded by Norman Doidge, as well as historical observations from outside the field of semiotics (Plato, Aristotle, Hume) shed further light on this process, and serve to further substantiate our semiotic and biosemiotic paradigm. Our analysis develops a rather limited associationism (with reference to Peirce’s categories) into a more general and robust interpretation that is applicable to all mind-bodies, whether they be neurons, paramecia and amoebae, or humans, cats and dogs. Biosemiotics is a more universal semiotics that takes us beyond the confines of anthropocentrism, because it recognizes the role of the body in shaping Mind. (shrink)

Communication and intentional behavior are supported by the brain’s integrity at a structural and a functional level. When widespread loss of cerebral connectivity is brought about as a result of a severe brain injury, in many cases patients are not capable of conscious interactive behavior and are said to suffer from disorders of consciousness (e.g., coma, vegetative state /unresponsive wakefulness syndrome, minimally conscious states). This lesion paradigm has offered not only clinical insights, as how to improve diagnosis, prognosis and treatment, (...) but also put forward scientific opportunities to study the brain’s plastic abilities. We here review interventional and observational studies performed in severely brain-injured patients with regards to recovery of consciousness. The study of the recovered conscious brain (spontaneous and/or after surgical or pharmacologic interventions), suggests a link between some specific brain areas and the capacity of the brain to sustain conscious experience, challenging at the same time the notion of fixed temporal boundaries in rehabilitative processes. Altered functional connectivity, cerebral structural reorganization as well as behavioral amelioration after invasive treatments will be discussed as the main indices for plasticity in these challenging patients. The study of patients with chronic disorders of consciousness may, thus, provide further insights not only at a clinical level (i.e., medical management and rehabilitation) but also from a scientific-theoretical perspective (i.e., the brain’s plastic abilities and the pursuit of the neural correlate of consciousness). (shrink)

Differentiating individuals by their voice is an important social skill for infants to acquire. In a previous study, we demonstrated that the ability to discriminate individuals by voice follows a pattern of perceptual narrowing (Friendly, et al., in press). Specifically, we found that the ability to discriminate between two foreign-species (rhesus monkey) voices decreased significantly between 6 and 12 months of age. Also during this period, there was a trend for the ability to discriminate human voices to increase. Here we (...) investigate the extent to which plasticity remains at 12 months, after perceptual narrowing has occurred. We found that 12-month-olds who received two weeks of monkey-voice training were significantly better at discriminating between rhesus monkey voices than untrained 12-month-olds. Furthermore, discrimination was reinstated to a level slightly better that of untrained 6-month-olds, suggesting that voice-processing abilities remain considerably plastic at the end of the first year. (shrink)

One of the most important recent developments in the study of concepts has been the resurgence of interest in nativist accounts of the human conceptual system. However, many theorists suppose that a key feature of neural organization—the brain’s plasticity—undermines the nativist approach to concept acquisition. We argue that, on the contrary, not only does the brain’s plasticity fail to undermine concept nativism, but a detailed examination of the neurological evidence actually provides powerful support for concept nativism.

With functional Magnetic Resonance Imaging (fMRI) of a memory-guided drawing task under both visual and blindfolded conditions, we have recently demonstrated that the primary visual cortex (V1) may play a role in implementing the visuo-spatial buffer or the sketchpad idea for working memory. We further proposed that it might however operate in a modality-independent, or amodal form, not restricted to the visual modality. In the present study, to further explore the role of V1 in non-visual memory, we eliminated not only (...) the visual input, but all levels of visual processing by training a congenitally blind novice to draw from tactile memory. The task of tactile exploration and memorization of the image to be drawn and a scribbling control task were also included. FMRI was run before training and after the consolidation of training by the novel Cognitive-Kinesthetic method. Remarkably, the primary visual cortex of this individual, which exhibited non-specific, noisy and immature transient responses before training, was massively recruited after training in the tactile-memory drawing task; moreover, after training, V1 produced normal, full-fledged response time-courses. The results reveal the operation of a rapid learning-based plasticity recruiting the visual cortex resources in the process of learning to draw. The learning paradigm allowed us to investigate for the first time the evolution of plastic re-assignment of the visual cortex. The fact that this re-assignment occurred in a congenitally blind subject, is consistent with an amodal nature of memory involvement of V1. The results specifically imply that such key mechanism can be empowered by the process of learning to draw. (shrink)

In this paper, I explore the idea that consciousness is something that the brain learns to do rather than an intrinsic property of certain neural states and not others. Starting from the idea that neural activity is inherently unconscious, the question thus becomes: How does the brain learn to be conscious? I suggest that consciousness arises as a result of the brain's continuous attempts at predicting not only the consequences of its actions on the world and on other agents, but (...) also the consequences of activity in one cerebral region on activity in other regions. By this account, the brain continuously and unconsciously learns to redescribe its own activity to itself, so developing systems of meta-representations that characterise and qualify the target first-order representations. Such learned redescriptions, enriched by the emotional value associated with them, form the basis of conscious experience. Learning and plasticity are thus central to consciousness, to the extent that experiences only occur in experiencers that have learned to know they possess certain first-order states and that have learned to care more about certain states than about others. This is what I call the “Radical Plasticity Thesis”. In a sense thus, this is the enactive perspective, but turned both inwards and (further) outwards. Consciousness involves “signal detection on the mind”; the mind is the brain's (non-conceptual, implicit) theory about itself. I illustrate these ideas through neural network models that simulate the relationships between performance and awareness in different tasks. (shrink)

Previous neuroimaging studies have demonstrated that musical expertise leads to functional alterations in language processing. We utilized diffusion tensor imaging (DTI) to investigate white matter plasticity in musicians with absolute pitch (AP), relative pitch (RP) and non-musicians (NM). Using diffusion tensor imaging (DTI), we analyzed the fractional anisotropy of the superior longitudinal fasciculus (SLF), which is considered the most primary pathway for processing and production of speech and music. In association with different levels of musical expertise, we found that (...) AP is characterized by a greater left than right asymmetry of fractional anisotropy (FA) in core fibres of the SLF. A voxel-based analysis revealed three clusters within the left hemisphere SLF that showed significant positive correlations with error rates only for AP-musicians in an AP-test, but not for musicians without AP. We therefore conclude that the SLF architecture in AP musicians is related to AP acuity. In order to reconcile our observations with general aspects of development of fibre bundles, we introduce the Pioneer Axon Thesis, a theoretical approach to formalize axonal arrangements of major white matter pathways. (shrink)

Consciousness is typically construed as being explainable purely in terms of either private, raw feels or higher-order, reflective representations. In contrast to this false dichotomy, we propose a new view of consciousness as an interactive, plastic phenomenon open to sociocultural influence. We take up our account of consciousness from the observation of radical cortical neuroplasticity in human development. Accordingly, we draw upon recent research on macroscopic neural networks, including the “default mode”, to illustrate cases in which an individual’s particular “connectome” (...) is shaped by encultured social practices that depend upon and influence phenomenal and reflective consciousness. On our account, the dynamically interacting connectivity of these networks bring about important individual differences in conscious experience and determine what is “present” in consciousness. Further, we argue that the organization of the brain into discrete anti-correlated networks supports the phenomenological distinction of prereflective and reflective consciousness, but we emphasize that this finding must be interpreted in light of the dynamic, category-resistant nature of consciousness. Our account motivates philosophical and empirical hypotheses regarding the appropriate time-scale and function of neuroplastic adaptation, the relation of high and low frequency neural activity to consciousness and cognitive plasticity, and the role of ritual social practices in neural development and cognitive function. (shrink)

In this paper, we present two neural network models - devoted to two specific and widely investigated aspects of multisensory integration - in order to evidence the potentialities of computational models to gain insight into the neural mechanisms underlying organization, development and plasticity of multisensory integration in the brain. The first model considers visual-auditory interaction in a midbrain structure named Superior Colliculus (SC). The model is able to reproduce and explain the main physiological features of multisensory integration in SC (...) neurons and to describe how SC integrative capability – not present at birth - develops gradually during postnatal life depending on sensory experience with cross-modal stimuli. The second model tackles the problem of how tactile stimuli on a body part and visual (or auditory) stimuli close to the same body part are integrated in multimodal parietal neurons to form the perception of peripersonal (i.e., near) space. The model investigates how the extension of peripersonal space - where multimodal integration occurs - may be modified by experience such as use of a tool to interact with the far space. The utility of the modelling approach relies on several aspects: i) The two models, although devoted to different problems and simulating different brain regions, share some common mechanisms (lateral inhibition and excitation, non-linear neuron characteristics, recurrent connections, competition, Hebbian rules of potentiation and depression) that may govern more generally the fusion of senses in the brain, and the learning and plasticity of multisensory integration. ii) The models may help interpretation of behavioural and psychophysical responses in terms of neural activity and synaptic connections. iii) The models can make testable predictions that can help guiding future experiments in order to validate, reject, or modify the main assumptions. (shrink)

Training studies, in which the structural or functional neurophysiology is compared before and after expertise is acquired, are increasingly being used as models for understanding the human brain’s potential for reorganization. It is proving difficult to use these results to answer basic and important questions like how task training leads to both specific and general changes in behaviour and how these changes correspond with modifications in the brain. The main culprit is the diversity of paradigms used as complex task models. (...) An assortment of activities ranging from juggling to deciphering Morse code has been reported. Even when working in the same general domain, few researchers use similar training models. New ways to meaningfully compare complex tasks are needed. We propose a method for characterizing and deconstructing the task requirements of complex training paradigms, which is suitable for application to both structural and functional neuroimaging studies. We believe this approach will aid brain plasticity research by making it easier to compare training paradigms, identify ‘missing puzzle pieces’, and encourage researchers to design training protocols to bridge these gaps. (shrink)

An important development in behavioural neuroscience in the past 20 years has been the demonstration that it is possible to stimulate functional recovery after cerebral injury in laboratory animals. Rodent models of cerebral injury provide an important tool for developing such rehabilitation programs. The models include analysis at different levels including detailed behavioural paradigms, electrophysiology, neuronal morphology, protein chemistry, and epigenetics. A significant challenge for the next 20 years will be the translation of this work to improve the outcome from (...) brain injury and disease in humans. Our goal in the article will be to synthesize the multidisciplinary laboratory work on brain plasticity and behaviour in the injured brain to inform the development of rehabilitation programs. (shrink)

The cerebellum is crucially important for motor control and motor adaptation. Recent non-invasive brain stimulation studies have indicated the possibility to alter the excitability of the cerebellum and its projections to the contralateral motor cortex, with behavioral consequences on motor control and motor adaptation. Here we sought to induce bidirectional spike-timing dependent plasticity (STDP)-like modifications of motor cortex (M1) excitability by application of paired associative stimulation (PAS) in healthy subjects. Conditioning stimulation over the right lateral cerebellum (CB) preceded focal (...) TMS of the left M1 hand area at an interstimulus interval of 2 ms (CB→M1 PAS2ms), 6 ms (CB→M1 PAS6ms) or 10 ms (CB→M1 PAS10ms) or randomly alternating intervals of 2 and 10 ms (CB→M1 PASControl). Effects of PAS on M1 excitability were assessed by the motor evoked potential (MEP) amplitude, short-interval intracortical inhibition (SICI), intracortical facilitation (ICF) and cerebellar-motor cortex inhibition (CBI) in the first dorsal interosseous muscle of the right hand. CB→M1 PAS2ms resulted in MEP potentiation, CB→M1 PAS6ms and CB→M1 PAS10ms in MEP depression, and CB→M1 PASControl in no change. The MEP changes lasted for 30-60 min after PAS. SICI and CBI decreased non-specifically after all PAS protocols, while ICF remained unaltered. The physiological mechanisms underlying these MEP changes are carefully discussed. Findings support the notion of bidirectional STDP-like plasticity in M1 mediated by associative stimulation of the cerebello-dentato-thalamo-cortical pathway and M1. Future studies may investigate the behavioral significance of this plasticity. (shrink)

The use of intracarotid propofol procedure (IPP) when assessing musical lateralization has not been reported in literature up to now. This procedure (similar to Wada Test) has provided the opportunity to investigate not only lateralization of language and memory functions on epileptic patients but also offers a functional mapping approach with superior spatial and temporal resolution to analyze the lateralization of musical abilities. Findings in literature suggest that musical training modifies functional and structural brain organization. We studied hemispheric lateralization in (...) a professional musician, a 33 years old woman with refractory left medial temporal lobe epilepsy. A longitudinal neuropsychological study was performed over a period of 21 months. Before epilepsy surgery, musical abilities, language and memory were tested during IPP by means of a novel and exhaustive neuropsychological battery focusing on the processing of music. We used a selection of stimuli to analyze listening, score reading, and tempo discrimination. Our results suggested that IPP is an excellent method to determine not only language, semantic and episodic memory, but also musical dominance in a professional musician who may be candidate for epilepsy surgery. Neuropsychological testing revealed that right hemisphere’s patient is involved in semantic and episodic musical memory processes, whereas her score reading and tempo processing require contribution from both hemispheres. At 1-year follow-up, outcome was excellent with respect to seizures and professional skills, meanwhile cognitive abilities improved. These findings indicate that IPP helps to predict who might be at risk for postoperative musical, language and memory deficits after epilepsy surgery. Our research suggests that musical expertise and epilepsy critically modifies long-term memory processes and induces brain structural and functional plasticity. (shrink)

Interest in the role of nitric oxide (NO) in the nervous system began with the demonstration that glutamate receptor activation in cerebellar slices causes the formation of a diffusible messenger with properties similar to those of the endothelium-derived relaxing factor. It is now clear that this is due to the Ca2+/calmodulin-dependent activation of the enzyme NO synthase, which forms NO and citrulline from the amino acid L-arginine. The cerebellum has very high levels of NO synthase, and although it has low (...) levels of guanylyl cyclase, cerebellar cyclic guanosine monophosphate (cGMP) levels are an order of magnitude higher than in other brain regions. A transcellular metabolic pathway is also present in the cerebellar cortex to recycle citrulline back to arginine. The NO formed binds to and activates soluble guanylyl cyclase to elevate cGMP levels in target cells. Studies employing NADPH-diaphorase, a selective histochemical marker for NO synthase, together with immunohistochemistry, in situ hybridization and biochemical studies have indicated that NO production occurs in granule and basket cells in the cerebellar cortex, whereas cGMP formation appears to occur largely in other cells, including Purkinje cells. Given that a long-term depression of AMPA currents can be seen in isolated Purkinje cells, this anatomical localization suggests that NO cannot play an essential role in the induction of this form of synaptic plasticity. (shrink)

The doctrine that the character of our perceptual knowledge is plastic, and can vary substantially with the theories embraced by the perceiver, has been criticized in a recent paper by Fodor. His arguments are based on certain experimental facts and theoretical approaches in cognitive psychology. My aim in this paper is threefold: (1) to show that Fodor's views on the impenetrability of perceptual processing do not secure a theory-neutral foundation for knowledge; (2) to show that his views on impenetrability are (...) almost certainly false; and (3) to provide some additional arguments for, and illustrations of, the theoretical character of all observation judgments. (shrink)

Cognitive penetration of perception, broadly understood, is the influence that the cognitive system has on a perceptual system (e.g., visual, auditory, haptic). The paper shows a form of cognitive penetration in the visual system (defined as early vision) which I call ‘architectural’. Architectural cognitive penetration is the process whereby the behaviour or the structure of the perceptual system is influenced by the cognitive system, which consequently may have an impact on the content of the perceptual experience. I scrutinize a study (...) in perceptual learning that provides empirical evidence that cognitive influences in the visual system produce neural reorganization in the primary visual cortex. The type of cognitive penetration can be synchronic and diachronic. (shrink)

Enzyme directed genetic mechanisms causing random DNA sequence alterations are ubiquitous in both eukaryotes and prokaryotes. A number of molecular geneticist have invoked adaptation through natural selection to account for this fact, however, alternative explanations have also flourished. The population geneticist G.C. Williams has dismissed the possibility of selection for mutator activity on a priori grounds. In this paper, I attempt a refutation of Williams' argument. In addition, I discuss some conceptual problems related to recent claims made by microbiologists on (...) the adaptiveness of molecular variety generators in the evolution of prokaryotes. A distinction is proposed between selection for mutations caused by a mutator activity and selection for the mutator activity proper. The latter requires a concept of fitness different from the one commonly used in microbiology. (shrink)

Cognitive control involves not only the ability to manage competing task demands, but also the ability to adapt task performance during learning. This study investigated how violation-, response-, and feedback-related electrophysiological (EEG) activity changes over time during language learning. Twenty-two Dutch learners of German classified short prepositional phrases presented serially as text. The phrases were initially presented without feedback during a pre-test phase, and then with feedback in a training phase spanning two days spaced one week apart. The stimuli included (...) grammatically correct phrases, as well as grammatical violations of gender and declension. Without feedback, participants' classification was near chance and did not improve over trials. During training with feedback, behavioral classification improved and violation responses appeared to both types of violation in the form of a P600. Feedback-related negative and positive components were also present from the first day of training. The results show changes in the electrophysiological responses in concert with improving behavioral discrimination, suggesting that the activity is related to grammar acquisition. (shrink)

Although the adult brain was once seen as a rather static organ, it is now clear that the organization of brain circuitry is constantly changing as a function of experience or learning. Yet, research also shows that learning is often specific to the trained stimuli and task, and does not improve performance on novel tasks, even very similar ones. This perspective examines the idea that systematic mental training, as cultivated by meditation, can induce learning that is not stimulus or task (...) specific, but process specific. Many meditation practices are explicitly designed to enhance specific, well-defined core cognitive processes. We will argue that this focus on enhancing core cognitive processes, as well as several general characteristics of meditation regimens, may specifically foster process-specific learning. To this end, we first define meditation and discuss key findings from recent neuroimaging studies of meditation. We then identify several characteristics of specific meditation training regimes that may determine process-specific learning. These characteristics include ongoing variability in stimulus input, the meta-cognitive nature of the processes trained, task difficulty, the focus on maintaining an optimal level of arousal, and the duration of training. Lastly, we discuss the methodological challenges that researchers face when attempting to control or characterize the multiple factors that may underlie meditation-training effects. (shrink)

The complete loss of visual awareness resulting from a lesion to the primary visual cortex (V1) suggests that this region is indispensable for conscious visual perception. There are however a number cases of conscious perception in the absence of V1 which appear to challenge this conclusion. These include reports of patients with bilateral V1 lesions sustained at an early age whose conscious vision has spontaneously recovered, as well as stroke patients who have recovered some conscious vision with the help of (...) rehabilitation programs. In addition, the phenomenon of hemianopic completion and percepts induced by brain stimulation suggest that V1 may not be necessary for conscious perception in all circumstances. Furthermore, that the visual abilities in the cat are associated with the recovery of normal extrastriate tuning properties rather than emulation of V1 functions suggests that there is nothing unique about the functional properties of this region in visual awareness. Rather, the dramatic effect of a V1 lesion on visual awareness may be due to its role in providing the majority of extrastriate visual input, the loss of which abolishes normal neural responsiveness throughout the visual cortex. (shrink)

Although musical skills clearly improve with training, pitch processing has generally been believed to be biologically determined by the behavior of brain stem neural mechanisms. Two main classes of pitch models have emerged over the last 50 years. Harmonic template models have been used to explain cross-channel integration of frequency information, and waveform periodicity models have been used to explain pitch discrimination that is much finer than the resolution of the auditory nerve. It has been proposed that harmonic templates are (...) learnt from repeated exposure to voice, and so it may also be possible to learn inharmonic templates from repeated exposure to inharmonic music instruments. This study investigated whether pitch-matching accuracy for inharmonic percussion instruments was better in people who have trained on these instruments and could reliably recognize their timbre. We found that adults who had trained with Indonesian gamelan instruments were better at recognizing and pitch-matching gamelan instruments than people with similar levels of music training, but no prior exposure to these instruments. These findings suggest that gamelan musicians were able to use inharmonic templates to support accurate pitch processing for these instruments. We suggest that recognition mechanisms based on spectrotemporal patterns of afferent auditory excitation in the early stages of pitch processing allow rapid priming of the lowest frequency partial of inharmonic timbres, explaining how music training can adapt pitch processing to different musical genres and instruments. (shrink)